Tunnelling often occurs in narrow spaces where it is required that an operator manually installs for example rock bolts and other types of supporting of rock. The manual installation of rock bolts includes an operator manually connecting an installation apparatus to a rock bolt. The installation apparatus comprises an installation arm connected to a pump system by means of which pressurisation of the rock bolt take place.
In the pressurisation, a pressure media, for example water, is pressed into the rock bolt by means of the pump system and more specifically a high-pressure pump, whereby the rock bolt is made to expand. The expanding of the rock bolt requires a pressurisation up to a certain level, and that this pressure is maintained for a period of time that is enough for the rock bolt to be allowed to expand.
The pump system used for pressurisation of rock bolts normally comprises a control system with a low intelligence, and which only strives to keep the pressure from the high-pressure pump constant at a prescribed installation level. The required pressure depends on type of rock bolt, but is often 240 or 300bar.
Between the rock bolt and high-pressure pump there is three way valve, the function of which is to open the flow of liquid into the rock bolt at pressurisation and to shut the flow of liquid from the pump when the installation is completed and then also to drain the rock bolt from the injected liquid. The three way valve is manipulated by the operator via a handle.
A problem with the present manual installation of rock bolts is that the installation procedure is difficult to handle for an operator. Since the operator applies the pressure by pressing in or releasing, respectively, a handle in an installation apparatus, the pressure may sometimes cease and it is also difficult for the operator to decide during how long time a certain pressure has been maintained, and thereby for how long the expansion of the rock bolt has been proceeded. It has turned out that an operator often overestimates the elapsed time when manually installing rock bolts, and is thereby inclined to interrupt the installation process prematurely. In rock bolting it has thus turned out that some of the rock bolts are insufficiently expanded, giving quality problems and inadequate reliability of the supporting of rock.
It would thus be desirable to provide an apparatus and method that simplifies and improves a manual installation of rock bolts.